When I reach around 18 PDFViewPWF instances (each in a tab) I get an exception.

Technical Support Apryse SDK
1

Question:
Here is the error I get

`

Message: bad allocation
Inner exception:
Stack trace:    at pdftron.PDF.PDFViewWPF.CreateTile(SByte* buffer, Int32 originX, Int32 originY, Int32 w, Int32 h, Int32 canvasNumber, Int64 cellNumber, Boolean finalRender, Boolean predictedRender, Int32 tiles_remaining, Boolean first_tile, Int32 canvas_width, Int32 canvas_height, Int32 cell_side_length, Int32 cell_per_row, Int32 cell_per_col, Int32 thumb_nail_id, Boolean swap_bytes, Int32 sequenceNumber)
   at pdftron.PDF.detail.CreateTile(Void* data, SByte* buffer, Int32 originX, Int32 originY, Int32 w, Int32 h, Int32 canvasNumber, Int64 cellNumber, Boolean finalRender, Boolean predictedRender, Int32 tiles_remaining, Boolean first_tile, Int32 canvas_width, Int32 canvas_height, Int32 cell_side_length, Int32 cell_per_row, Int32 cell_per_col, Int32 thumb_nail_id, Boolean swap_bytes)

`

How do I handle this?

Answer:
You need to use the following two functions to activate and deactivate your PDFViewWPF instances. Ideally just one is Active at any given time, to minimize memory usage.

PDFViewWPF.Deactivate()

PDFViewWPF.Activate()

2

When a PDFViewWPF goes out of view, you can call PDFViewWPF.Deactivate, and it release all memory except what is currently visible on the screen. Activate will subsequently resume the viewer, including pre-rendering content off screen. Using this should save you a lot of memory.

For example usage of these, see the PDFViewWPFTest sample, and how these functions are used in MainWindow.xaml.cs.